Yn ppn c physical address format 11 10 9 8 7 d

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Unformatted text preview: d VP 2 to PP 7. Similarly, the page table for process maps VP 1 to PP 7 and VP 2 to PP 10. Notice that multiple virtual pages can be mapped to the same shared physical page.
Virtual address spaces
0 Physical memory
0 Address Translation VP 1 VP 2 Process i:
N-1 0 Shared page
VP 1 VP 2 Process j:
N-1 M-1 Figure 10.9: How VM provides processes with separate address spaces. The operating maintains a separate page table for each process in the system. The combination of demand paging and separate virtual address spaces has a profound impact on the way that memory is used and managed in a system. In particular, VM simpliﬁes linking and loading, the sharing of code and data, and allocating memory to applications. 10.4.1 Simplifying Linking
A separate address space allows each process to use the same basic format for its memory image, regardless of where the code and data actually reside in physical memory. For example, every Linux process uses the format shown in Figure 10.10. The text section always starts at virtu...
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